Ceramic panels suitable for industrial applications should meet requirements such as convenient and simple constructability upon structural changes of buildings, and should be light weight in compliance with a trend toward scale-up and higher stories of buildings. In addition, panels should have effects such as heat conservation/insulation in order to cut down on consumption of energy, and sound absorption/insulation against a variety of noises due to high densities of buildings in cities.
Conventional autoclaved lightweight concrete (ALC) panels or blocks, domestically produced by some manufacturers, have been partially adopted on construction sites by building companies, but suffer from problems associated with water permeability, incongruence of wiring and piping work and excessive weight, thereby making it difficult to acquire popularity in the related art.
Dry walls, a type of building material which is used by assembling and constructing individual members on construction sites utilizing gypsum boards, glass wool and steel studs, also suffer from disadvantages such as significant error and variation during or after installation, weak impact strength and weak nail-bearing strength, thus resulting in inferior housing quality. Additionally, due to their poor water resistance, water absorption of glass wool resulting from water leakage leads to growth of fungi, thereby failing to acquire popularity and application thereof.
Foam glass, a glass having a pore structure inside thereof, is an amorphous material exhibiting heat insulation and light-weight characteristics due to physical properties of the pore structure in combination with inherent physical properties of glass itself. Foam glass is widely used as a heat-insulating material, a cold-insulating material and a corrosion-resistant material in various applications such as petrochemical plants, bottoms of LNG tanks, freezing warehouses and chimney linings.
In addition to those panel materials as mentioned above, there is an extrusion lightweight aerated concrete panel such as Acotec panel, but such a panel also suffers from disadvantages such as heavy weight and poor processability, thereby resulting in very little application.
Such conventional lightweight panels are susceptible to many problems such as risk of bacterial proliferation in seasons of high-humidity resulting from their high water-permeability, excessive weight and low nail-bearing strength upon installation thereof in large-sized buildings, and poor sound-insulation and flame retardancy characteristics in densely built-up city buildings.
Meanwhile, sandwich panels, in which plate-like materials such as steel plates are attached to both sides of core materials such as heat insulating materials, are used as interior and exterior work materials for buildings such as temporary buildings, non-residential buildings, partition wall structures and exterior wall structures.
Conventional sandwich panels may be broadly divided into an expandable polystyrene panel (EPS), an expanded polyurethane panel, a polyisocyanurate (PIR) panel and a glass wool panel, depending upon species of internal heat-insulating materials.
Among these panels, the EPS panels and expanded polyurethane panels cannot secure fire-resistant performance, and thus cannot be applied to sites which are required to be fireproof. Further, these panels cannot secure incombustibility performance, thereby being applicable to very limited sites and cannot be applied to sites that can be seen from inside, thus limiting practical uses and applications thereof.
The PIR panel exhibits incombustibility performance of flame retardancy grade 3, but is incapable of securing fire-resistant performance. Therefore, this panel cannot be applied to sites requiring incombustibility performance of flame retardancy grade higher than 2 or fire-resistant performance, and is also disadvantageously expensive.
The glass fiber panel can ensure fire-resistant performance and thus can be applied to various sites, while exposure of the panel to water cause fatal damage thereof due to its vulnerability to water, thus reducing the functions of the sandwich panel. In addition, due to dust of glass fibers occurring when cutting and installing the panel, there is a disadvantage such as avoidance of construction by workers.
Korean Patent Publication Laid-open No. 1992-0017801 and Korean Patent Registration No. 135439 disclose a sandwich panel comprising a heat-insulating material composed of a foam resin as an intermediate inserting material and a polymer concrete as an exterior wall material. Korean Patent Publication Laid-open No. 2001-0003718 discloses a thin stone sandwich panel for a prefabricated partition manufactured by making a multi- or mono-layer block having a cavity formed inside thereof using a stone plate material, filling the cavity with materials such as concrete waste and then cutting and trimming the stone material, and a boundary stone for sidewalks and roadways. Korean Utility Model Registration No. 344475 discloses a sandwich panel in which an internal space of a hollow hexahedron-shaped sandwich panel skin is filled with lightweight aerated concrete via an injection process. However, such conventional sandwich panels have disadvantages such as heavy weight and poor processability due to the use of concrete or stone materials.
As such, conventional sandwich panels suffer from a variety of problems such as potential risk of bacterial proliferation in seasons of high-humidity due to their high water-permeability, excessive weight and weak nail-bearing strength upon installation thereof in large-scale buildings, and poor sound insulation and flame retardancy characteristics in densely built-up city buildings.
In order to ensure that sandwich panels are free from many limitations associated with their application, the panels should have incombustibility and fire-resistance performance, and in order to achieve the desired degree of customer satisfaction for products, the panels should provide superior sound insulation, bending strength, impact strength, nail-bearing strength, water resistance and durability characteristics.